HOWTO Setup Logrotate
Biggest headache is that /var/log/auth.log and vsftpd.log do not rotate :-(
Fix this by creating /etc/logrotate.d/vsftpd:
/var/log/vsftpd.log { weekly sharedscripts missingok notifempty postrotate /etc/init.d/vsftpd restart > /dev/null 2>&1 || true endscript }
Edit the portion of /etc/logrotate.d/syslog-ng to look like this:
# Authentication /var/log/auth.log { weekly sharedscripts missingok postrotate /etc/init.d/syslog-ng reload > /dev/null 2>&1 || true endscript }